The major objective of ths proposal is to enhance and expand the capabilities of an institutional Microscopy Shared Resource Facility (SRF) at Mount Sinai School of Medicine. Improvements to this core facility will significantly enhance the research efforts of NCI-funded (and other NIH-funded) investigators throughout the institution. Improvements will be developed on three fronts: a) live cell imaging; b) molecular localization, and c) digital image acquisition and image analysis. In addition to enhancing the capabilities of the facility, overall operating costs will be lowered, thus making the facility more accessible (financially) to junior investigators. The specific aims are: 1) to provide increased access by NCI- and other NIH-funded investigators to state-of-the-art instrumentation and high quality, cost effective microscopy services by reducing user fees charged; 2) to educate and train NCI-funded investigators in the use of advanced microscopy and imaging techniques in cancer research; 3) to promote NCI-funded use of the Microscopy SRF by adding an NCI-funded investigator to the Microscopy SRF advisory committee; 4) to enhance live-cell (live-tissue) imaging capabilities, including multi-photon laser scanning microscopy, by providing equipment to support vital imaging (e.g. cell culture equipment, heated microscope stages) on site and by hiring a technician to assist with live cell / confocal / multi-photon imaging; 5) to improve user-friendliness of electron microscopy and decrease turn-around time for EM results by installing digital image acquisition system (cCCD camera) on the electron microscope; and 6) to enhance ultrastructural immunolocalization capabilities by including cyro-fixation, freeze-substitution, and cryo-ultramicrotomy techniques to our options for immunolocalization by electron microscopy. Representative studies from 16 NCI funded labs (representing 7 departments at MSSM) have been highlighted in the Research Plan of this grant proposal. Successful organizational, operational, and business plans are already in place. In addition to the use training activities already well established within the core, plans are being developed to expand the educational efforts of the core (including a graduate school course, lectures, and multi-media learning materials).